Pope Francis waves to people gathered in St. Peter's Square at the Vatican as he arrives on June 4, 2014, for his weekly general audience. / Tizana Fabi, AFP/Getty Images

by Eric J. Lyman, Special for USA TODAY

by Eric J. Lyman, Special for USA TODAY

VATICAN CITY - If he manages to make progress in brokering peace between Israeli and Palestinian leaders this weekend, Pope Francis, who has broken ground at almost every opportunity during his 15-month papacy, will have outdone himself.

Vatican officials stress Sunday's encounter - accepted by Israeli President Shimon Peres and Palestinian President Mahmoud Abbas two weeks ago when Francis handed down an unexpected invitation during his three-day visit to the Middle East - is spiritual rather than political. But for a region entrenched in conflict for millenniums, any agreement by Israeli and Palestinian leaders to join together to discuss peace - in whatever context - is big news.

"This is a pope who truly believes in the power of prayer, who believes it can help solve even the most intractable problems," says Andrea Tornielli, who covers the Vatican for the Italian daily La Stampa. "Last September, he dedicated a day to pray for peace in Syria, but this is even more significant because he's invited leaders of the main parties to join him and pray together."

During his trip to the Holy Land, Francis called for the recognition of a Palestinian state, long the main sticking point in peace efforts in the region. Although he stayed away from the prickly details of such a plan - most notably, where the borders of a new Palestinian state would be or any timetable - there is hope discussions of that topic might be forthcoming.

"It's a spiritual meeting, but the hope among those involved is that it will lay the groundwork for future diplomatic initiatives," says Marco Ansaldo, a Vatican expert with the Rome daily La Repubblica.

Many obstacles remain. But if there is significant progress where recent diplomatic forays from Secretary of State John Kerry and others have stalled, it will prove the so-called "Francis Effect" - credited with achievements ranging from reviving church attendance to repairing the church's image battered by sex abuse and financial scandal - has staked out new geopolitical territory.

For the faithful in Rome, the details of Sunday's meeting and what it might lead to are less important than the growing perception that Francis seems willing to try to take on any issue, no matter how difficult.

"The Holy Father is making a step toward resolving what seems like an unsolvable problem," says Maria Tavares de Silva, a 41-year-old Brazilian nun based in Rome. "All we can do is join him with our own prayers and hope for signs of peace."

Marco Antonio Delemonte, 55, a social worker and a regular visitor to papal audiences in St. Peter's Square, goes further in his assessment.

"There have been problems between Jews and Muslims and Christians in that part of the world since biblical times," Delemonte says. "If the pope can help broker peace, I think we will have to ask ourselves: Is there anything he cannot do?"